DSP Zippers

[tgstgs]

im very sure you know cos otherwise your not be able to create so fantastic device;
so i guess there is only one vocable in english to define 2 sort of probl. which has nothing to do with each other
so please at least call them zippering1 and zippering2

1. feed a sinus to an amplifier and create a so called zippering effect to hear;
-> you still see the sinus looking outzoomed continous
you had to zoom in to see the steps (spices) where created-> you hear as zippering;
this is simple valuechangings;

2. feed a sinus to masterverb (forgive that i will only talk about 1st party no 3rd party verbs of what developer ever!)
-> you didnt even have to zoom in to see the trouble;
it looks like my 5 year old son cuttes the sinus in peaces putting it together afterwards;
this is cutted buffer contend;
its like switching phase random + valuechangings
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please correct me if im wrong so far
never dived into a reverbalgo!!
had such probl. often in non audiorelated stuff
but you know buffer is buffer and data is data
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if adding an interpolation (whatsort ever is best to apply) it would help for probl. Nr.1;
but for probl. Nr2 you will change the wave more or less drastically as you said;
i dont understand why this all!?
how you select the smaples being interpolated? (them all?!)
how you know if its the cutting (switching) and not present in the wave you feed?
why you clean after?
---------
here we go
developer decide what settings are possible
you know befor if switching from A to B may be trouble and you know what sort of trouble;
so you know if its better to interpolate or crossfade for example
and you are able to tell how much samples befor and after the cut are nessersary to process;
more you are able to disallow scope4lives random changings or delay his changings to a time which is more suitable to the algo;
by changings on the fly you may jump for A to C missing B if the changings are made fast to minimize noise, dont?
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so i would first raster the variable contend of buffers to non noise sizes;
(a variable time raster cos 0crossings are frequency depending)
thiswhise your able to tell which valuechangings or bufferswitches are coursing trouble then decide the algo to eleminate;
+ allow only these settings freuqency/time depending which suits your needs;
your even able to manipulate the bufferconted to fit the changings;
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man sitting in the dark here in vienna hope man from denmark brings light;


good vibes

[Warp69]

I imagine that the test file I posted earlier is part of zippering2, right?

There exist different types of transients elimination algorithms, like :

* Crossfading
* Gradual variation using interpolation - this is the one I would use in a reverb. (works like a chorus effect)
* Modified superposition
* Update state-vector

The last one can completely eliminate transients, bu have some drawbacks.

Cheers

[dawman]

WOW !!

Thanks for looking into this tgstgs, and Brotha' Man Warp69.

What are the drawbacks you speak of?

If it can't be performed effectively, oh well we tried.

As far as zippering goes. Could changing the rates of a super multi tap as in the Ursa Major be achieved with DSP with no artifacts?

And as far as the Plate example goes, I use the Hall algo which seems to avoid the deadly zippers. Maybe this isn't consistent with all algos.

I currently use GigaPulse for my ER's, and the Lexicon's for the rooms, etc. w/o zippers or artifacts.

I really need a 12 tap emu of the Ursa Major, as I could change the rates to go from a longer rate ( delay / echo ), to a tighter msec. rate for a tape style reverb. I currently use the 3 headed Tape Sim from Celmo for get ting close to what I've described, but it suffers from artifacts as well when changing rates. Too bad, as the sound of that device on my polyphonic synth patches is to die for. But I still use it on most of my ProWave Presets live. I just have a preset for each ProWave preset, and leave the 3 heads ( taps ) alone.

Warp69,
Did you ever use a Lexicon 12bit Prime Time w/ the ARP Odyssey style fader caps?
That delay was awesome, and displayed no artifacts when changing the rates.
My PCM81 does this well also, but the number of taps is limited.



Thanks 4 Your Efforts, I am very busy this weekend, but look forward to discussing this with you early next week.


Brotha' Man tgstgs,.......are you a developer in exile or something?

[tgstgs]

time will tell
-----
btw the total zawinul concert is not canceled!!!!!!!!!!!!!!!!!!!!!!!!!1
they make a total zawinul without zawinul;
they plan to show him on videowall!
crazy istn it

good vibes

[dawman]

I hope I can see it.

What do you think of my Giant Multi Tap Delay / Tape Reverb ?

[Warp69]

And as far as the Plate example goes, I use the Hall algo which seems to avoid the deadly zippers. Maybe this isn't consistent with all algos.

I respectfully disagree.

Warp69,
Did you ever use a Lexicon 12bit Prime Time w/ the ARP Odyssey style fader caps?
That delay was awesome, and displayed no artifacts when changing the rates.
My PCM81 does this well also, but the number of taps is limited.

Nope - I have never used a Lexicon Prime Time or PCM42. But many use the PCM42 before the digital reverbs as a predelay.

Cheers

[dawman]

With Kind Regards,
Gentlemens disagreements are the best kind.


Is such a large tap device possible?

I would love to have such a device that has no zippers when changing the rates. It acts like a giant multi-tap delay, which is the kind of sound effects that give percussive poly-synth comps a great tail. It could also be used as a psuedo reverb when the rates are lowered in the msec. range.

If there were " zippers " they might not be as noticable. This is similar to changing a reverb room size, as the space increases or diminishes for the appropriate effect.

I have no idea if it's possible, but if it is, I would gladly buy one. As the new Ursa emu is not as capable as it's hardware predecessor.

That was a synth players dream. As was the Prime Time, PCM41, and PCM42's were quite noble.


Thanks For Your Replies,

[hifiboom]

whats the use of being able to modify the room_size in real time?

just wondering?

[hubird]

in gaming, entering another 'room' it'll make it more realistic
in serious music it'll be alienating, which is eh...musical

[hifiboom]

lol play all games with a plate reverb and feel bigger.

[dawman]

Well I hear the zippers on the PCM's now. But they aren't noticable unless you change the size and gate slowly which thankfully I don't do. I never heard these on the PCM70, where you could tie several parameters to your Mod Wheel for this style of playing. I slide my finger on my ribbon controller to change the size, but am changing to an expression pedal as soon as it arrives. That MIDI Solutions FP8 is gonna be nice. I would rather use my feet, so I can keep both hands playing.

I use this technique when ending a song where you can go from your selected algo to an infinite reverb for the songs ending.

I especially like this on horn sections where I am using a gated reverb, and wish to reduce the length of the gate and room size simultaneously. It adds separation to the instruments in a live mix.

As far as changing room size in a video game, which BTW was a good example, I am sure the engineer could punch in as he follows the SMPTE code.

But this is no big deal, but in DSP / VST reverbs this is quite noticable. But I am sure when they designed these devices they weren't thinking about anything other than realistic sound emulations.

I still would like one that could come close to my examples with out all of the inherant noises.

I wonder if it is possible to make a 12 tap delay that could morph into a reverb like the effect that the old Ursa Major had. It was not designed to simulate rooms, or anything in particular but it sure had a great sound on my Oberheim back then. You had to physically change the parameters, just like the Lexicon Prime Time, PCM 41, or PCM 42. MIDI was still a gleam in somebody's eye at Yamaha back then.

[Warp69]

With Kind Regards,
Gentlemens disagreements are the best kind.


Is such a large tap device possible?

I would love to have such a device that has no zippers when changing the rates. It acts like a giant multi-tap delay, which is the kind of sound effects that give percussive poly-synth comps a great tail. It could also be used as a psuedo reverb when the rates are lowered in the msec. range.

If there were " zippers " they might not be as noticable. This is similar to changing a reverb room size, as the space increases or diminishes for the appropriate effect.

I have no idea if it's possible, but if it is, I would gladly buy one. As the new Ursa emu is not as capable as it's hardware predecessor.

That was a synth players dream. As was the Prime Time, PCM41, and PCM42's were quite noble.


Thanks For Your Replies,

Its possible to do a Ursa Major Space Station emulation (ADR68K do not have those algoritms), but I don't see a Size parameter on the Space Station - It would be extremely difficult to emulate the SST-282 without the actual unit.

The unit have different tap patterns, but no Size parameter.

[Shroomz~>]

Its possible to change that - you'll have to use modulation delaylines, but if you use linear interpolaters you'll get some lowpass filter effect.

The mod delays are very heavy on dsp consumption & the lowpass filter effect is quite extreme. Not so bad with a nice wet/dry balance, but very very noticeable when used fully wet.

regards,
S

[Warp69]

Regarding the dsp consumption - the reason for that is probably the use of internal ram on the dsp's.

You could use higher order lagrange to minimize the lowpass effect. But in reverbs its not that important, since there are alot of delay lines and it wont be that noticeable.

[Shroomz~>]

Yes, I'm pretty sure you're right with regards to the dsp consumption.

[dawman]

There's no size on the hardware units, but rather rate ( speed ) which when shortened are similar to tightening up a space from a hall to a room kind of.

There are a couple on ebay and they are still quite expensive.

I found a close enough sound of that multi tap reverb thing in Celmos little KB mixer. As long as you set it and don't move the parameters it sounds good.


Brotha' Man Warp69, do you have a site I can visit. I would love to see some of your stuff. You obviously have many great harsware units, and know a great deal about applying this to DSP based FX.



Thanks everyone for their replies on this matter.

[Warp69]

I have www.relab.dk - nothing special, since most of it is hidden for the public.

[dawman]

Thanks,

Very nice indeed.

Miraslav Philharmonic ?

These will work in GS4 via VST.

I must investigate PlanetZ's favorite reverb developer further.

[Warp69]

Right now - Im busy with CSR2.

But development is slow right now, because of new toy - Roland R880 V2 reverb

Cheers

[hifiboom]

CSR2 ?

I thought you were building the 480L for scope.